Automatic concrete forming machine for producing high density products

ABSTRACT

A machine capable of producing various shaped high density concrete products automatically when its associated mechanical components, including a pre-shaped mold box, insertable and retractable core plugs and tiltable double faced tamping device are caused to perform their specific functions in timed sequence.

United States Patent Moore Dec. 25, 1973 AUTOMATIC CONCRETE FoRMlNG2,680,276 6/1954 Filangeri 249 64 MACHINE FOR PRODUCING HIGH 2,512,0926/1950 Dike et al. 425/424 X 2,256,361 9 1941 Straub 425 424 x DENSITYPRODUCTS 3,078,539 2/1963 Duplessis 425 421 x Inventor: Leon E. Moore,1240 S. 31st Ave.,

Phoenix, Ariz.

Filed: Dec. 16, 1971 Appl. No.: 208,589

US. Cl 425/424, 425/428, 425/456 Int. Cl B2811 l/00 Field of Search425/421, 424, 431,

References Cited UNITED STATES PATENTS 5/1928 Straub .l 425/425 PrimaryExaminer-Robert D. Baldwin Assistant ExaminerJohn McQuadeAtt0rney-Warren F. B. Lindsley [5 7 ABSTRACT A machine capable ofproducing various shaped high density concrete products automaticallywhen its associated mechanical components, including a preshaped moldbox, insertable and retractable core plugs and tiltable double facedtamping device are caused to perform their specific functions in timedsequence.

5 Claims, 14 Drawing Figures PATENTEHBEEZS'Q 3,781.15

SHEET 1 0F 4 I INVENTOR. Ls'o/v ET Moons.

PATENTEDUEE25I975 atmmss ATTDRNEX PATENTEH DEBZ 5 I973 SHEET 0F 4 I NVEN TOR LEO/V A. MOORE.

wax ATTORNEY AUTOMATIC CONCRETE FORMING MACHINE FOR PRODUCING HIGHDENSITY PRODUCTS BACKGROUND OF THE INVENTION This invention relates tomachines for producing high density concrete products.

1. Field of the Invention This invention is particularly directed to aconcrete forming machine which utilizes a combination of hydraulic andpneumatic power to operate the functioning components of the machine inproper sequence to automatically produce high density concrete productshaving greater strength at a low cost.

2. Description of the Prior Art Heretofore small items such as watermeter boxes, building blocks, fence components and the like have notbeen successfully made out of high density concrete since the time andlabor necessary was prohibitive. Thus, a need exists for these highdensity items, particularly since they last much longer in use than thesame item made out of normal density concrete.

SUMMARY OF THE INVENTION In accordance with the invention claimed, animproved concrete forming machine is provided which may be operated byone man to automatically and speedily produce high density concreteproducts having the necessary strength required for various structuraluses, such as water meter boxes (shown), building blocks, fencecomponents and the like.

It is, therefore, one object of this invention to provide a new andimproved apparatus for forming automatically high density products.

Another object of this invention is to provide an improved machine forforming high density water meter boxes from concrete.

A further object of this invention is to provide an improved moldloading, pressing and core removing apparatus for sequentially forming aplurality of like concrete products by a single operator.

A still further object of this invention is to provide high densityconcrete products from a dry mix automatically and sequentially at a lowcost.

Further objects and advantages of the invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize this invention will be pointed out with particularity inthe claims annexed to and forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS section on the line 33 of FIG. Iillustrating the elevator mechanism of the invention.

FIG. 4 is a fragmentary sectional plan view taken substantially on line4-4 of FIGS. 1 and 2 illustrating the relation of the core plugs to themold box of the invention.

FIG. 5 is a fragmentary vertical sectional view taken substantially online 55 of FIG. 1 illustrating the tiltable double faced tamping deviceof the invention.

FIG. 6 is a fragmentary vertical sectional view taken on the line 6-6 ofFIG. 4, through the stationary mold box and work counter illustratingthe initial respective positions of the retractable core plugs andelevator mechanism when these elements are static and the mold box isempty, ready to receive the raw concrete material to form the highdensity concrete meter box.

FIG. 7 is an enlarged fragmentary view similar to FIG. 6 illustratingthe first step or sequence of operation of the machine required tofabricate the product, showing the core plugs inserted into the mold boxand the cavity of the mold box loosely filled with a raw concretemixture, and the main tamper foot in position for activation.

FIG. 8 is a view similar to FIG. 7, illustrating the next step orsequence of operation of the machine and showing the concrete mixturecompacted by successive reciprocal movements of the main tamper foot tooccupy approximately one half the vertical height of the mold boxcavity.

FIG. 9 is a view similar to FIG. 7, illustrating the next step orsequence of operation and showing the upper half portion of the mold boxcavity loosely filled with the raw concrete mixture to its extreme topwith the dual tamping member having been tilted or rotated ninetydegrees to bring the top or finishing tamper foot into position foractivation.

FIG. 10 is a view similar to FIG. 9, illustrating the next step orsequence of operation and showing the upper one half portion of theloosely filled concrete mixture in the mold box cavity after compactionby successive reciprocal movements of the top or finishing tamper foot,thereby completing the necessary operations required for producing ahigh density concrete water meter box.

FIG. 11 is a view similar to FIG. 10 illustrating the final step orsequence of operation of the machine required to make ready for removalof the finished meter box from the machine by a lift truck or othersuitable equipment, and shows the core plugs retracted from the mold boxand the finished meter box raised to a position several inches above thework counter surface, still supported by a removable ring member on theupward projecting tines of the elevator mechanism.

FIG. 12 is a schematic diagram illustrating the hydraulic systememployed for operating and controlling some elements of the machine.

FIG. 13 is a schematic diagram illustrating the pneumatic systememployed for operating and controlling other elements of the machine.

FIG. 14 is a perspective view of the finished meter box still supportedon the removable ring ready for air curing and storage.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the severalviews of the drawings for a more detailed description of theconstruction and other features of the invention by characters ofreference, FIGS. 1 and 2 illustrate the complete assembled automaticconcrete forming machine 10 of this invention, which comprises the rigidstructural frame 1 I having secured thereto between the verticallydisposed I beam members I2 and 13 of the frame a rigid counter top orwork table structure 14. Work table structure 14 is adapted to support apreformed mold box 15 in intergral relation therewith by means oftransverse structural members 16.

A material supply delivery chute 17, having upwardly extending flangedsides 18, is directly connected to similar flanged sides 19 which areintegral with and extend upwardly from the top surface 20 of the worktable structure 14, in any suitable manner such as by welding, toprovide a raw material delivery source to the top surface 20 of the worktable from a material mixer (not shown).

The vertical l-beam members 12 and 13 of the frame structure 11 arerigidly connected at their upper ends by a transverse I-beam member 21and at their bottom ends by a heavy support plate member 22 which ispreferably embedded in a concrete slab 23 and securely anchored theretoby suitable anchor bolts 24. The entire rectangular structural frame 11is further rigidly maintained in a plumb vertical position by means ofthe horizontal tie bars 25 and/or other structural support members (notshown).

Surrounding the lower ends of the vertical I-beam members 12 and 13 andextending transversely therebetween, while providing suitable clearancefrom said members, is an elevator mechanism 26 which is adapted to restin its lowermost position slightly above the surface of plate member 22on stops, such as the heads of anchor bolts 24. The purpose and functionof the elevator mechanism 26 will be further explained as thisdescription proceeds.

Mounted between and adjacent the flat inner surfaces of the verticalI-beam members 12 and 13 in the upper portion of the frame 1 1 is aU-shaped reciprocating frame member 27, to the lower flange 28 of whichis attached by welding or otherwise a pair of depending angle members29. Angle members 29 are adapted to support in rotative relation thetiltable double-faced tamping device 30. The U-shaped frame 27 andattached tamping device 30 are supported and reciprocated down and up asa single unit by means of the rigid attachment 31 of the frame to thelower extending end of piston rod 32 which protrudes from the bottom endof its operating pneumatic cylinder D.

It is imperative that the moving and stationary components of theconcrete forming machine 10 so far described must be maintained in nearperfect vertical and horizontal aligned relationship during theoperation of the machine. Misalignment of any of said components wouldcause improper contact and possible rupture of the machine parts anddestruction ofthe product being fabricated. To prevent such anoccurrence, the moving components of the machine such as elevator 26 andU- frame 27 with its supported tamping device 30 are maintained invertical and horizontal alignment with stationary work table 14 and itsassociated mold box 15 by means of a plurality of eccentricallyadjustable rollers 33. Rollers 33 are suitably spaced and mounted on themoving components and adapted to provide rolling contact with the flatinner or outer faces and the forward or rearward projecting edgesurfaces of the legs of the vertical l-beams 12 and 13, as shown inFIGS. 1 and 2.

The preformed mold box 15, utilized to fabricate or automaticallyproduce the desired finished product, for example, a high densityconcrete water meter box or housing 34 shown in FIG. 14, rests on itsindividual, re-

movable retaining ring 35. Housing 34 and ring 35 are removed frommachine 10 after a molding operation so that housing 34 may be set asidefor air curing. The housing 34 is substantially a hollow cube in formhaving narrow perpendicular side walls 36 with rounded outside comersdefining a rectangularly cross-sectional configuration. The housing isadditionally provided with a flat bottom surface 37 and a top endsurface 38 defining a rectangular opening 39 exposing a hollow interior40 which extends from top to bottom of the cube. The perpendicular walls36 are thickened at their top inside surfaces to provide a suitableledge 41 which extends around the inside perimeter of the walls tosupport the usual metal meter box cover (not shown). The ends of box 34are also provided with suitable arched openings 42 which extend to andthrough the bottom surfaces 37 of the box to allow for the passage ofvarious size pipes (not shown) during installation of the meter box.

The mold box 15 is preformed to fabricate the water meter box describedin the preceding paragraph or any other desired product and comprisesexterior, continuous wall 43 forming the perimeter of the box which,together with the centrally located interior core member 44 having aflat closed top 45 and a closed bottom 46, forms the continuousrectangular mold cavity 47. The width of the cavity is substantially thesame as the desired wall thickness of the finished meter box 34. Theexterior opposite ends of walls 43 and the adjacent opposite end wallsof the interior core member 44 are each provided with arcuate toppedcutouts or openings 48 and 49, respectively, which are adapted toreceive in sliding relation suitably shaped, insertable and retractablecore plugs 50 and 51, respectively. These core plugs are adapted to formthe arched openings 42 in the finished meter box 34.

The preformed mold box 15 is centrally located and preferably installedmidway between the inside surfaces of the vertical I-beams 12 and 13,and the flange sides 19 of the work table structure 14, which in turnare rigidly connected by means of bolts or otherwise to the insidesurfaces of the l-beams. The mold box 15 is also rigidly supported byand secured at its bottom end to the transverse structural members 16which form an integral part of the work table structure 14. Thecontinuous perpendicular side walls 52 of the interior core member 44being accurately spaced an equal distance inwardly from the inside faceof the exterior walls 43 to form the mold cavity 47 is open at both itsupper and lower ends 53 and 54 to allow for raising and removal tosecure and support the unattached interior core member 44 in its spacedrelation from the exterior walls 43 by suitable cross ties 55. Thesecross ties are preferably welded to the closed bottom 46 of the coremember and to the transverse structural member 16 as shown in FIGS. 1,4, and 6 through 11.

The top surface 20 of the work table 14 is provided with an opening 56which mates with exterior perimeter wall 43 of the mold box 15, intowhich it extends and is secured by welding to form the outer perimeterof the mold cavity 47.'The mold cavity 47 extends to the top surface 20of the work table 14 and together with the flat closed top 45 of theinterior core member 44 forms a wide open end 53 of the cavity, whichforms a material receiving access opening 53' in the top surface 20 ofthe work table 14.

The elevator mechanism 26 which is used to support the concrete watermeter box 34 in the process of fabrication and to lift the finished boxup and out of the mold cavity 47 isbest illustrated in FIGS. 1, 2 and 3.This elevator mechanism 26 comprises a pair of front and rear transversestructural I-beams 57 and 58, respectively, which extend across thefront and rear of the vertical I-beams l2 and 13, and at their outerends are joined, as by welding, to upwardly extending side plate members59 and 60, and to the pairs of front and rear angular reinforcing platemembers 61. These described structural components are adapted to form anopen-topped box-like structure, which surrounds but which has clearancefrom the vertical I-beam members 12 and 13. The box-like structure maybe easily raised and lowered in exact alignment with the other machinecomponents, such as the mold box 15, by means of the eccentricallyadjustable rollers 33, which contact and roll on the outside faces andfront and rear edge surfaces of the vertical I-beam members 12 and 13.

Integral with or removably secured to the top surfaces of the I-beams 57and 58 is a flat plate member 62 to which are attached a plurality offlat-topped rods or tines 62' which project perpendicularly to, and arelocated on the plate member 62 to extend slightly into the center of themold cavity 47. At this point their flat tops are utilized to supportone of the individual retaining rings 35, upon the top surface of whichthe water meter box 34 is being formed.

The structural portion of the elevator mechanism 26 may be raised orlowered as desired by the controlled simultaneous action of thehydraulically operated cylinders B and C, shown in FIG. 12, which areeach universally mounted at 63 between the rearwardly extending legs ofthe vertical I-beams l2 and 13 shown in FIGS. 1 and 3. As the liftingapparatus associated with hydraulic cylinders B and C are identical, itwill suffice to describe only one of them, which is shown in detail inFIG. 3 on the right side of the machine.

The lower ends of piston rods 64 of cylinders B and C are connected at65 to the upper ends of a bifurcated bar or fork member 66 which areadapted to straddle a plate 67. Plate 67 is integrally attached to thetop face of the rear transverse I-beam 58 and projects inwardlytherefrom, between the sides of the fork members 66. Directly belowplate 67, mounted in the sides of fork member 66, is a transverse pin orbolt 68. A stop plate 69 is secured in horizontal position by welding tothe rear side of the vertical I-beam web 70 and limits the downwardmovement of the fork member 66. Near the top of fork members 66, betweentheir inner sides, and

journaled on a shaft 71, is a freely rotatable idler sprocket 72, overwhich a suitable link chain 63 is adapted to ride. Chain 63 is securedat its forward bottom end 74 to [beam web 70 and at its rearward bottomend 75 to plate 70.

It should be noted that chain 73 is somewhat longer than necessary,thereby resulting in a bulged or slack portion in the rear portion ofthe chain as at 76, when the elevator mechanism 26 is in its at-restposition as shown in FIGS. 1 and 3. This condition provides for a slowand gentle upward initial movement of the elevator mechanism with itsassociated lifting tines 62' contacting the retaining ring 35 to causethe initial breaking away of the walls of the completed water meter box34 from the walls of the mold cavity 47 without damage to the finishedproduct. This slow and gentle initial lifting movement becomes faster aschain 73 overrides the idler sprocket 72 and becomes taut, therebyquickly lifting the finished meter box from its forming mold as shown inFIG. 11.

Referring now to FIGS. 1, 4, 6, 11 and 12 of the drawings, these figuresshow the core plugs 50 and 51 in their retracted or inserted positionsto perform their particular function of forming the arched openings 42in the end walls of the concrete meter box 34. A hydraulic mechanism inassociation with these core plugs is utilized to perform the intricatefunction of inserting and retracting these plugs. The core plugs 50 and51 are formed to the desired arched top, straight sided and openbottomed shape of openings 42 and are provided with a central bore 77which extends through the plugs. The reduced outer end portions 78 ofplugs 50 and 51 have flat top and bottom surfaces to which are attachedthe bifurcated, rigid lever arms 79 which extend rearward and parallelto the side flange portions 19 of the fixed work table structure 14. Atthis point 80 the lever arms are integrally connected to the inwardlyprojecting, right angle extension portions 81 and 82, respectively, ofthe lever arms 79. Top and bottom portions of extensions 81 and 82 arejoined to the bifurcated lever arms 79 at 80 and at their inner opposedends 83 by connecting blocks which form lever arms 79, and their rightangle extensions 81 and 82. This connection forms a pair of L-shapedunits. When these L-shaped units are activated by means of thehydraulically operated cylinder A, they will cause core plugs 50 and 51to be moved inwardly or outwardly substantially at the same time so asto either insert or retract the core plugs into or from openings 48 and49 of the mold box 15.

To accomplish this result, the opposed extensions 81 and 82 of leverarms 79 are provided with suitable bores therethrough for receiving atransverse shaft 84. Shaft 84 is fixed at its opposite ends to flangedsides 19 of the work table 14 to firmly support in sliding relationthereon the opposed lever arm assemblies. The fixed transverse shaft 84is also provided with adjustable stop collars 85 which limit the inwardmovement of these lever arms.

The core plugs 50 and 51 are slidably mounted in their bores 77 oninwardly projecting studs 86 which are fixed in exact horizontal andvertical alignment with the centers of the mold box cutouts 48 and 49 tothe rear legs of the vertical I-beams 12 and 13. This arrangement firmlysupports the core plugs as they are moved in and out during fabricationof the meter box. It should be noted that the core plugs 50 and 51 areprovided with smooth flat bottomed surfaces 87 which are adapted toslide easily and directly on the smooth, flat top surface 88 of theindividual retaining rings 35 as shown in FIGS. 6 through 10, inclusive,when said rings have been inserted in the mold cavity 47, resting on theflat top ends of the support rods 62.

The hydraulic operated cylinder A is mounted directly forward of and inparallel alignment with the transverse shaft 84 and is pivotally securedon one end at 89 to one of the lever arms 79. Its piston rod 90 ispivotally secured at 91 to the other and opposite lever arm 79. CylinderA is provided at each end with suitable hydraulic lines or hoses 92 and93 which supply the necessary oil pressure to move the piston shaft and-/or the cylinder itself in the desired direction, to retract or insertthe core plugs 50 and 51 from the openings 58 and 59 in the walls of themold box 15, as desired, to complete the fabrication of the meter box34.

FIGS. 1, 2 and 5 of the drawings illustrate the various features of thenovel tiltable, double-faced or footed tamping device 30 used inconjunction with the other components of the complete assembled machineto fabricate the concrete meter box 34. In these figures device 30 isshown in its normal, at-rest position, relative to the other machinecomponents, or ready to begin the initial fabricating operation of theproduct.

The tiltable, double-footed tamping device 30 comprises a suitablyshaped body structure 92' to which is integrally attached the forwardfacing finishing foot 93' and the downward facing main foot 94 which arepositioned at right angles to each other, as shown in FIG. 5. The maintamping foot 94 is a continuous flat bottom surfaced ring which issimilarly shaped to retaining rings 35; but is much narrower in crosssection, as shown in FIG. 8, to allow for escape of air from the moldbox cavity 34 during its tamping function. The finishing foot 93' has aslightly curved tamping surface 95 forming a part of the integral formedring flange 96, which together with the curved tamping surface 95 areadapted to finish the curved top end surface 38 and the continuous ledge41 of meter box 34, as shown in FIG. 1 and 11 of the drawings.

The tamping device 30 is provided with an integral sleeve 97 whichextends transversely between the side walls of the body structure 92 andis provided with a central bore and bearing surface through which thetransverse axle shaft 98 extends. Shaft 98 is supported at both ends bythe depending angle members 29 in tiltable or rotative relation to thereciprocal U-frame member 27, as previously described.

Tamping device 30 may be tilted to bring the finishing foot 93' (asshown in full lines in FIG. 5) into position for the finish tampingoperation (as shown in dotted line in FIG. 5) by the activation of thepneumatically operated air cylinder E. Cylinder E is pivotally mountedat its top end to the arm of bracket 99 which is secured to the frontface of U-frame web 100, clearly shown in FIG. 1. Cylinder Es piston rod101 extends downward through a slot 102 in the lower flange 28 of theU-frame, where its lower end is pivotally attached at 103 to theadjacent upper side wall of the tamping device body structure 92.

Cylinder E may be activated through the control valve (A-2) which ismounted on the front of the U- frame member 27 and receives its supplyof air under pressure through flexible hose or line 104 from a source ofpressurized air supply such as the compressor 105 which is driven by amotor 106 (see FIG. 13).

Control valve A-2 is connected to the top of cylinder E by an air supplyline 107 to the bottom of cylinder E by an air supply line 108. Whenvalve A-2 is positioned, as shown in FIG. 13, air under pressure will bedelivered to the top of piston 109, causing the piston and its attachedpiston rod 101 to be forced downwardly, thereby applying force to thepivotal attachment 103 at the point where the end of the piston rod isconnected to the body structure 92 of the tamping device 30. This causesthe pivotal point of attachment to move radially in an are about theaxis of the transverse axle shaft 98, causing the entire tamping deviceto be tilted or rotated exactly 90, bringing the finishing foot 93' intotamping position for use as shown in dotted line in FIG. 5.

When it is desired to tilt the tamping device 30 back to its originalposition, shown in full lines in FIG. 5, with the main tamping foot 94in position for use, this reverse tilting movement may be readilyaccomplished by adjusting the valve A-2 to allow pressurized air to movethrough line 108 to the bottom of cylinder E, thereby forcing piston 109upwardly and retracting the piston rod into the cylinder. This actioncauses the tamping device 30 to be returned to its original position.The air on the downstream side of the piston is exhausted during eithercycle of movement through suitable exhaust ports, such as exhaust port110 in valve A-2. Set screws 111 are provided in the lower flange 28 ofthe U-frame member 27 which contact the top edges of the body structure92 of the tamping device. These set screws may be adjusted to maintainthe tilting radial movement of the device to more or less, as desiredfor accurate alignment of the tamping device.

The tamping device 30 and the U-frame member 27 to which it is attachedare designed to be reciprocated as a single unit, down and up in avertical direction between the vertical I-beams 12 and 13. Theadjustable rollers 33 maintain accurate vertical and horizontalalignment of the tamping device 30, and especially its tamping feet 93and 94, with respect to the mold cavity 47 and the access opening 53' inthe table top surface 20, as shown in FIGS. 7 through 11.

The downward force or thrust on the U-frame member 27 and its associatedtamping device 30 required to perform the tamping function is providedby the combined weight of the unit and the operation of the large andpowerful pneumatic cylinder D. The top of cylinder D is pivotallymounted at 112, midway between the vertical I-beam members 12 and 13 tothe top transverse I-beam 21, from which it extends verticallydownwardly. Its piston rod 32 extends downward from its bottom and isrigidly attached at 31 to the center of the transverse web of thereciprocating U-frame member 27, as shown in FIG. 1.

The lower end of cylinder D is provided with a frame structure 113 whichstraddles the web 100 of the U- frame member and is provided on itslower surface with two pairs of flexible rubber bumpers 114. Thesebumpers are adapted to contact the upper surface of the U- frame memberslower transverse flange 28 to absorb the initial shock on cylinder Dwhen the U-frame member is sequentially returned during the tampingoperations to its upper position, thereby preventing damage to thecylinder D and its associated elements.

Cylinder D is provided at its upper end with a flexible air-line hose115 which extends through an opening in the leg of vertical I-beam framemember 13 and downwardly to where it is connected to the main doubleacting control valve A-l. Control valve A-I receives pressurized airthrough a line 116 from compressor 105. Cylinder D is provided at itslower end with a suitable fitting which supports a quick relief valveA-3 which is also connected through a flexible air line hose 117 toanother port in the control valve A-l. The quick acting relief valve A-3provides instant relief of any residual pressure in the lower portion ofcylinder D to thus increase the downward velocity of the tamper foot.

OPERATION Reference is now made to the sequence of operation of themachine as shown in FIGS. 7 through 11 of the drawing and to theschematic diagrams of the hydraulic and pneumatic systems shown in FIGS.12 and 13 illustrating the operation of the machine in fabricating ahigh density concrete water meter box shown in FIG. 14. It should benoted that the various components of the machine shown in FIGS. 1-6 arein their respective positions at the start of a fabrication or formingoperatron.

The first step in the operation of the machine is to insert core plugs50 and 51 into openings 48 and 49 in the ends of mold box 15. This isaccomplished by actuating or positioning the hydraulic control valveV-l, as shown in dotted lines, to allow oil under pressure from asuitable pump 118 to move through feed line 119, valve V-l and its line120., and line 92 into cylinder A, causing piston rod 90 to be retractedinto cylinder A, pulling lever arm 79 toward one side of the mold box15. This action causes core plug 51 to be inserted into the openings inone end of the mold box. Core plug 51 is stopped at the desired positionby contact of end 83 of extension 82 with one of the adjusting collars85, immediately after which the core plug 50 on the opposite side of themold box is caused to be inserted in the openings 48 and 49 in theopposite end of the mold box. This action occurs by the continued oilpressure on the piston of cylinder A, which causes the cylinder itselfto be moved laterally, together with the attached lever arm 79-81 untilthe end of lever arm 81 is stopped against the other stop collar 85,thereby resulting in the proper insertion and'positioning of both coreplugs 50 and 51 in the mold box 15 as required to continue thefabrication of the meter box.

After the core plugs 50 and 51 have been inserted in the mold box 15, asabove described, a predetermined amount of premixed but raw concretematerial is delivered down the chute 17 from the mixer (not shown) tothe rear top surface 20 of the work table structure 14. Approximatelyone half of this material is scraped from the table top surface 20 intothe mold box cavity 47 to completely fill said cavity to its upper openend 53 with this loose material resting on the flat top surface 88 ofthe individual retaining ring 35. Ring 35 has previously been placed inthe mold cavity 74, where it rests on the top flat surfaces of theelevator rods or tines 62'. The material in the mold cavity 47 surroundscore plugs 50 and 51, as shown in FIG. 7.

The loose material in the mold cavity 47 is then tamped, as shown inFIG. 8, by the reciprocating action of the main tamping foot 94 of thetamping device 30 and by the combined weight of said device and theassociated U-frame member 27. The downward thrust is created when airpressure is applied to the top of the piston in the pneumatic cylinder Dwhen the control valve A-l is repeatedly activated to provide thisaction. This action results in the loose material being compacted into adense mass which occupies approximately one half of the height of themold cavity 47.

The remainder of the material left on the table surface 20 is thenplaced into the mold cavity 47 directly on top of the previouslycompacted material which cupies the lower half of the cavity representedin FIG. 9 by the broken line 120. This remainder material fills theupper half of the mold cavity 37 with loose material which extendsslightly above the upper open end of the access opening 53' in the tabletop. After this second filling of the remaining cavity space isaccomplished, the tamping device 30 is tilted or rotated 90 to bring thefinishing tamping foot 93' into alignment with the top surface 20 of thework table structure 14 and the access opening 53 of the mold cavity 47.This tilting action is accomplished by the activation of the pneumaticvalve A-2 as previously described. This upper half portion of loosematerial is then compacted into a dense mass by the reciprocating actionof the tamping device 30 and the U-frame member 27 in the same manner asthe lower portion of the material was compacted by the main tamping foot94, described above.

The tamping action of the finishing foot 93 results not only in thecompaction of the upper portion of loose material into a dense mass, butalso joins the upper and lower portions of compacted material into asingle homogeneous, perpendicular wall structure 36 which forms themeter box 34. In addition the tamping foot 93 provides for the formationof the continuous ledge 41 in the interior of the meter box, resultingin a slightly curved top end surface 38 to the finished meter box 34, asshown in FIGS. 11 and 14. It should also be understood that the degreeof compaction of the loose concrete material is carefully controlled bythe number of reciprocal tamping movements of the tamping feet to assurethe desired finished height of the meter box 34.

Since the meter box 34 has been completely formed by the precedingoperations, as shown in FIG. 10, it only remains necessary to carefullyremove the finished meter box from the preformed mold box 15 withoutdamage to the uncured box and to place the box on a suitable rack forair curing.

Reference should now be made to the sequence views of FIGS. 10 and 11and the schematic diagrams shown in FIGS. 12 and 13 for explanation ofthe final operation of removing the finished meter box 34 from themachine. The pneumatic control valve A-l should be adjusted to allow airunder pressure to enter the cylinder D at its lower end. This occurs byair pressure passing from the compressor through line 116, line 121 ofthe valve A-l, line 117, and automatic relief valve A-l to the bottom ofcylinder D, thus causing the finishing tamper foot 93', the tampingdevice 30 and the reciprocating U-frame member 27 to be raised to itsnormal (at-rest) position as shown in FIG. 1. This apparatus ismaintained in this position by the continued pressure of air on theunderside of the piston in cylinder D. The spent air is evacuated toatmosphere from the top of the cylinder through the line and exhaustport 112 (shown in dotted line) in valve A-l.

During the above operation all of the ports in the tilt valve A-2 may beadjusted so that a port 123 (shown in dotted line) in the valve is incommunication with the air lines 104 and 108, thus causing piston 109 incylinder E to be raised (as shown in FIG. 13), and the spent air abovethe piston to be evacuated to atmosphere through line 107, port 124(shown in dotted line) in the valve A-2, and exhaust port 1 10. Thisoperation results in the return of the tiltable tamping device 30 to itsnormal position as shown in FIGS. 1 and 13, i.e. with the main tampingfoot 94 facing downward ready to resume its tamping function on anothermeter box unit.

The next step or operation required is the removal of the core plugs 50and 51 from their position in the mold cavity 47 of the mold box 15.This is accomplished by reversal of the procedure as previouslydescribed for the insertion of the core plugs into the cavity 47 of themold box. Hydraulic control valve V-l is adjusted to let oil underpressure from the pump 118 move through line 119, valve V-I and line 93into the end of cylinder A where it exerts pressure on the piston (notshown). This action causes piston rod 90 to retract lever arms 79 and 82and core plug 51 from the mold box cavity 47, as shown in FIGS. 11 and12, to a position flush against the flanged side 19 of the work table 14which stops the outward movement of the core plug 51. Continuedhydraulic pressure on the piston in cylinder A which is stopped fromfurther lateral movement causes cylinder A itself to be moved outwardlytogether with lever arms 79 and 81, thereby retracting core plug 50 fromthe mold box cavity 47, as shown in FIG. 11.

During the above described operation, hydraulic fluid or oil from theopposite side of the piston in cylinder A is returned to a reservoir 125through line 92, valve V-l, line 126 and the interconnected return line127. A suitable relief valve 128 is connected between the pressure line119 and the return line 127 to prevent any sudden surges of pressurefrom being exerted on the valves V-l and V-2 or other components in thehydraulic system to provide a smooth uninterrupted operation of theseparts.

Having thus removed the tamping device 30 and the core plugs 50 and 51from any possible interference with the final removal of the finishedconcrete meter box 34 and its retaining ring 35 from the mold box, themeter box and retaining ring are removed from the mold box as follows:

Hydraulic control valves V-l and V-2 are adjusted to allow fluid underpressure to pass from source 106 through line 119, valve V-l, the upperportion of line 93, to and through valve V-2, to line 129, which isconnected to the interconnecting line 130 which communicates with thelower ends of the hydraulically operated cylinders B and C as shown inFIG. 12. The pressure applied to the cylinders B and C simultaneously isadapted to raise the pistons in both cylinders, thus lifting theelevator mechanism 26 (as previously described) from its at-restposition shown in FIGS. 1 and 2, together with tines 62' which are incontact with the flat underside surface of the retaining ring 35, theretaining ring 35 and the meter box 34 resting on its upper surface 88.This raising action occurs very slowly for the first one half inch or soto gently break the perpendicular walls 36 of the meter box from theadjacent walls of the mold cavity 47, thereby protecting the walls ofthe newly formed meter box from damage which might otherwise be incurredby a sudden movement of the tines 62'.

After this slow initial upward movement of the elevator mechanism theremaining lift of the retaining ring 35 and the uncured concrete meterbox 34 is quickly accomplished by the faster upward movement of thetines 62' to a position several inches above the top surface of the worktable 14. Enough space is provided between the top surface of the worktable and the retaining ring to allow for the insertion of the fork ortines of a lift truck under the retaining ring 35 to lift and remove themeter box from the machine and place it on a suitable storage rack forair and water curing.

Having thus quickly fabricated and removed one finished high densityconcrete meter box from the machine, the machine is quickly arranged forsequential production of additional boxes by valve V-2 being positionedto allow the elevator mechanism to return by gravity to its originallower starting position (shown in FIG. 1). The hydraulic fluid incylinders B and C is caused to return to reservoir through theinterconnecting line 130, line 129, port 131 in the valve V-2 (shown indotted line) and return line 125.

Although but one embodiment of the invention has been shown anddescribed, it will be apparent to those skilled in the art that variouschanges and modifications may be made therein without departing from thespirit of the invention or from the scope of the appended claims.

I claim:

1. A molding apparatus comprising:

a mold box open at its top and bottom,

a vertically arranged core disposed within said mold box and spacedtherefrom to form a space around the core between the mold box and thecore,

a molding ring disposed within said space between said mold box and saidcore at the lower end of said mold box and arranged to close the lowerend of said space,

said molding ring being slidably movable in said space,

a means for supporting said molding ring at the bottom of said space insaid mold box,

said mold box defining an opening extending laterally of its top andbottom and extending into said space between said mold box and saidcore,

a core plug reciprocally mounted on said apparatus for movement into andout of said opening,

said core plug being inserted into said opening during a moldingoperation and being retracted from said opening prior to a mold boxevactuating operation,

a tamping mechanism mounted on said apparatus for reciprocally movinginto the opening at the top of said mold box and said space between saidmold box and said core for compacting material previously placed in saidspace,

means for sequentially actuating said tamping mechanism to tightlycompress the compressible material, and

means for slidably moving said mounting ring in said mold box from itsbottom to its top for pushing the compacted material from said mold box,

said tamping mechanism comprises a pair of tamping rings,

one of said tamping rings having a cross-sectional configuration similarto the cross-sectional configuration of the lower part of said space,

the other of said tamping rings having a flange extending downwardlyinto said space along its inner periphery for providing a ridge alongthe inside of the compacted material, and

means for sequentially tamping the material with said first tamping ringand then with said other tamping ring. 4

2. The molding apparatus set forth in claim 1 wherein said latter meansactuates said first tamping ring a number of times before itsequentially actuates said other tamping ring a number of times.

3. The molding apparatus set forth in claim 1 wherein:

said mold box defines two openings extending into said mold boxlaterally of its longitudinal axis and along a common axis, and

a pair of core plugs reciprocally mounted on said apparatus, one formovement into and out of each of said openings.

mold box and said core without damaging the compacted material.

5. The molding apparatus set forth in claim 3 in further combinationwith loading means for sequentially loading said space between the coreand the mold box before each sequential actuation of said means fortamping the material.

1. A molding apparatus comprising: a mold box open at its top andbottom, a vertically arranged core disposed within said mold box andspaced therefrom to form a space around the core between the mold boxand the core, a molding ring disposed within said space between saidmold box and said core at the lower end of said mold box and arranged toclose the lower end of said space, said molding ring being slidablymovable in said space, a means for supporting said molding ring at thebottom of said space in said mold box, said mold box defining an openingextending laterally of its top and bottom and extending into said spacebetweEn said mold box and said core, a core plug reciprocally mounted onsaid apparatus for movement into and out of said opening, said core plugbeing inserted into said opening during a molding operation and beingretracted from said opening prior to a mold box evactuating operation, atamping mechanism mounted on said apparatus for reciprocally moving intothe opening at the top of said mold box and said space between said moldbox and said core for compacting material previously placed in saidspace, means for sequentially actuating said tamping mechanism totightly compress the compressible material, and means for slidablymoving said mounting ring in said mold box from its bottom to its topfor pushing the compacted material from said mold box, said tampingmechanism comprises a pair of tamping rings, one of said tamping ringshaving a cross-sectional configuration similar to the cross-sectionalconfiguration of the lower part of said space, the other of said tampingrings having a flange extending downwardly into said space along itsinner periphery for providing a ridge along the inside of the compactedmaterial, and means for sequentially tamping the material with saidfirst tamping ring and then with said other tamping ring.
 2. The moldingapparatus set forth in claim 1 wherein said latter means actuates saidfirst tamping ring a number of times before it sequentially actuatessaid other tamping ring a number of times.
 3. The molding apparatus setforth in claim 1 wherein: said mold box defines two openings extendinginto said mold box laterally of its longitudinal axis and along a commonaxis, and a pair of core plugs reciprocally mounted on said apparatus,one for movement into and out of each of said openings.
 4. The moldingapparatus set forth in claim 1 wherein: said latter means comprising ahydraulic cylinder connected to said mounting ring through a chain andsprocket drive first slowly and then more rapidly actuates said mountingring through said space between said mold box and said core to overcomethe adhesion of the compacted material to said mold box and said corewithout damaging the compacted material.
 5. The molding apparatus setforth in claim 3 in further combination with loading means forsequentially loading said space between the core and the mold box beforeeach sequential actuation of said means for tamping the material.